This invention relates to electric circuit breaker panelboards and more particularly to such panelboards which utilize a plug-in circuit breaker as a main disconnect circuit breaker to provide service disconnect capability for the panelboard. Specifically, the invention relates to a bracket which may be assembled to the panelboard in the field which inhibits the removal of the main circuit breaker from the panelboard by a mere unplugging or pulling action.
Distributors of electrical panelboard apparatus stock a high proportion of panelboards which have lug main connectors provided thereon and which are suitable for use as feeder panelboards. However, to qualify as service entrance equipment, it is necessary to provide a main disconnect switch for the panelboard whereby power to the panelboard may be interrupted by operating the switch. This is accomplished by providing a two or three pole circuit breaker on the panelboard and connecting the incoming supply wires to the circuit breaker to thereby feed the panelboard bus through that circuit breaker. To protect against the electrical hazards that may exist if the main circuit breaker is unplugged from the panelboard while wired and under power by an unauthorized or unknowledgable workman, it is preferred to provide a means of securing that circuit breaker to the panelboard which will require consideration and the use of a tool in order to affect its removal. Copending patent application entitled "Electrical Panelboard With Main Breaker Hold-Down" in the name of Donald A. Link and John A. Swessel Jr. and assigned to the Assignee of this application discloses one form of hold-down means which may be factory installed on a panelboard assembled solely for main circuit breaker service disconnect application. This means comprises a Z-shaped bracket which bolts to the panel at one horizontal leg thereof and has the opposite horizontal leg overlying the front surface of the main breaker. This device may not be used on panelboards having lug main provisions because the bracket is installed in the area which is occupied by the lug mains. Moreover, a specially notched deadfront cover is required for that panelboard to permit the forward end of the Z-shaped bracket to extend over the front surface of the main breaker. Other hold-down devices have been provided for main circuit breakers for panelboards in the past, but these devices generally required removal of the panel from the installation in order to gain side access to the panel to remove the hold-down device. This is, of course, objectionable to the electrician servicing the panel.